Recloser mechanism



Septr24, 1963 s. c sw 3,105,129

' RECLOSER MECHANISM Filed March 1 1961 4 Sheets-Sheet 1 I 29 I FIG.I

FIGJA INVEN TOR.

Arthur S.Coswel| BY drreaze/w. 51552,?595 ffiFFEA ATTORNEYS.

RECLOSER MECHANISM Filed March 1, 1961 4 Sheets-Sheet 2 FIG.2 3

INVENTOR. Arthur S. Coswell BY Uri/Pa e44 6955?, 95a; Java/v ATTORNEYS.

P 24, 1963 A. s. cAsWE-LL 3,

RECLOSER MECHANISM Filed March 1, 1961 4 Sheet-Shet s INVENTOR. Arthur S.Coswell ATTORNEYS.

United States Patent 3,itl5,12 RECLGSER MEQHANISM Arthur S. Caswell, Greensburg, Pa, assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Mar. 1, 1961, Ser. No. 92,596 9 Claims. (Cl. 20tl-92) This application is a continuation in part of my copending application Serial No. 859,003, filed December 11, 1959, entitled Circuit Breaker Closing Mechanism, and assigned to the assignee of the instant invention. The invention of this application relates to a circuit breaker operating mechanism utilizing power operated cam means for closing and having features whereby this mechanism is coordinated with the operation of an automatic reclosing timer integrator.

In the prior art, circuit breaker operating mechanisms of the type which will hereinafter described were operated by push or pull rods or cam means requiring a separate and distinct latch, known as a prop latch, to maintain the contacts in closed position. With this arrangement closing travel must be sufficiently long to assure that the prop latch will drop in at the end of the closing stroke and pick up the load of the opening springs. 'In order to eliminate the necessity for providing a prop latch, some prior art mechanisms are provided with overcenter toggle mechanisms which are extremely ineflicient and often present certain problems when the toggle is in dead center position.

In circuit breakers of the automatic reclosing type having prior art operating mechanisms as outlined above, a special switch is utilized as a check to assure that the main trip latch is fully reset. This is necessary to prevent false closing operations. The force required to operate the switch made it necessary to utilize a strong latch reset spring. Often the trip load became more than the ordinary overload devices could produce so that it became necessary to add impact trip means.

The switch described above was usually a microswitch which interrupted the closing circuit until main latch reset. This type of switch is a poor interrupter of DC. current which is customarily used for control circuits.

The disadvantages of the prior art as outlined above are overcome by the instant invention which provides a collapsible linkage having a trip latch which normally maintains the linkage in an extended position. A cam means driven by a motor through a clutch mechanism acts upon the extended collapsible linkage to drivethe circuit breaker contacts into engagement.

The-cam engages a roller carried by the collapsible linkage for driving the latter. A depression is provided in the cam-to receive the roller and act as a prop latch when the circuit breaker contacts are engaged. The depression is so constructed and positioned that as the roller enters the depression the force of the circuit breaker opening spring acts to rotate the cam in the direction which the motor has been driving the cam.

At the moment the roller first enters the depression the motor energizing circuit is interrupted. The circuit breaking opening spring continues to drive the cam thereby effectively removing the load on the clutch mechanism. At this time the cam operates to disengage the clutch and finally the linkage roller comes to rest in thelow spot of the depression.

The depression is so constructed that when the roller is in the low spot the roller is engaged at two points by the cam. 'Thiseifectively divides the load produced by the opening spring between the two points of contact rather than being restricted to a single point of contact as in prior art devices.

This is an extremely important feature in electric Patented Sept. 24, 1 963 distribution equipment in that the circuit breaker, once closed, will probably remain in this position for years. The constant pressure between two surfaces bearing against each other produces a how of material at one or the other of the surfaces. By dividing the load between two contact points the tendency for the material to flow is materially reduced so that reliable operation will be assured if the need arises. V

This invention also provides a mechanical means to check the trip latch to prevent initiating a closing operation before the trip latch is fully reset. This means comprises a simple member movable with the trip latch into and out of a recess provided in a member which carries the contacts for initiating the closing operation of the circuit breaker. If the trip latch is not fully reset the member is positioned with-in the recess and blocks closing of the closing initiating switch.

Accordingly, a primary object of this invention is to provide a novel circuit breaker closing mechanism which utilizes a cam device for positioning the contacts.

Another object is to provide a circuit breaker mechanism having a cam with a depression of novel configura tion to provide a prop latch.

Still another object is to provide a novel circuit breaker operating mechanism including a trip latch which acts on the knee of a collapsible linkage, the linkage being operable by the cam of the linkage.

A further object is to provide a circuit breaker mechanism which includes a novel mechanical latch to check the position of the trip latch and assure that the trip latch is fully reset before a closing operation can be initiated.

These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a side elevation of a circuit breaker constructed in accordance with the teachings of the instant invention with the near side of the tank cut away to reveal the closing mechanism which is in a reset position with the contacts open. In FIGURE 1, for the sake of clarity, only the center phase of the circuit breaker is illustrated FIGURE 1A is an enlarged detail illustrating the linkage roller in the cam prop latch depression.

FIGURE 2 is an enlarged side elevation of the closing cam showing the manner in which it operates the closing initiating switch to the open position.

FIGURE 3 is an end view of the elements illustrated in FIGURE 2 looking in the direction of arrows 3-3 of FIGURE 2.

FIGURE 4 is a cross section taken through line 4-4 of FIGURE 3 looking in the direction of arrows 44.

FIGURE 5 is a partial elevation of the operating mechanism looking in the direction of arrows 5-5 of FIGURE 1.

FIGURE 6 is a plan view of the member.

FIGURE 6A is an end view of the releasing member of FIGURE 6 looking in the direction of arrows 6--6.

FIGURE 7 is a cross section taken through line 77 of FIGURE 2 looking in the direction of arrows 77.

FIGURE 8 is a schematic diagram of a closing circuit.

Now referring to, the figures, circuit breaker 10 is a clutch releasing three-phase unit each phase of which is provided with means in engagement with one end.

ground shields 2,2, 23 respectively with two current transformer-s 24, 25 surrounding ground shields 23.

' At'each side of mechanism 30, and assembled to cover 1-7, is a box enclosure 29 for the complete automatic recl osing timer-integrator controls, and another enclosure 2% for the auxiliary switch (not shown), operation counter 92, and visible position indicator 93, each of whichform no part of this invention, as well as for closing motor 28. Shaft 27, connected to mechanism 30' at pivot 50 by links 93, 99 joined at pivot 97 projects into enclosures 29 and 29a to operate the required components therein in a manner well known to the art.

' tion 71 is fixedly mounted to cover 17 at projections 73.

Motor 28 is a universal AC, DC. motor which a serves to providethe motivating force for the closing of circuit breaker 10. The output shaft of motor-'28 drives the input of a'set of reduction gears 31 whose out-.

i put drives miterfv gear 32 which is. keyed to shaft 3 3. I

Miter gear 32 in turn drives miter gear34, keyed to shaft portion 35 which carries clutch member 36 thereon.

Clutch member 37, keyed to shaft portion 38,- is biased by compression spring 39 toward engagement with clutch member 36. Shaft portions and 38 are axiallyaligned V and form a single shaft 35, 38. Gear34 and clutch member 36are' integrally formed and are free to rotate with respect tojshaft portion 35 except when clutch members 36,37 are in operative engagement. Shaft 35, 33 includes a portion 38a of square cross-section which provides a rotational axis for closing cam 40 mounted thereon. t

Carn 46 is a plate-like member whose edge 41 is in operative engagement with cam roller 42. mounted to one'end of guide arm 43 whose other end is mounted to stationary pivot 44. The olosing force exerted by cam 40 is transmitted through 'the collapsible toggle linkage comprising links 45, 46 to interrupter contact operating lever 47. One end of link is mounted to guide arm ;43at pivot 48 about which cam roller 42 is rotatable, The other end of link 45 is joined to one end of link 46 at the knee 49 of toggle-linkage 45, 46 while the other endiof link 46' is pivotally mounted at 'tie rod 50 to operating lever 47.

' In the resetposition of mechanism 30 (FIGURE 1),

toggle linkage 45, 46 is restrained against collapsing by trip finger 51pivoted to stationary pivot .52. Finger 51 provides a trip latch whose free end engages roller 53 at one end of link 54. The other end of link 54 is keyed to stationary shaft 55 towhich one end of link 56 is also keyed. The other end of link 56 is pivoted at 57 to one end of link 58-whose other end is joined to toggle linkage 45, 46 at knee49.

Operating lever 47 is pivoted intermediate the ends thereof about pin 59 with the long end of lever 47 operating through tie rod 66' and links 61' to move rods 62' of interrupter units 12 downwardly during closing of circuit breaker 14 The lower ends of rods 62 carry the movable contact means of" interruptersyIZ in a 'manner well knownto'the art.

During closingtravel of lever 47, opening springs 63 operativelo'ver the full closing stroke, are charged.

Springs 63 are housed in a pair of. guide tubes 64 with each spring 63 bearing against the end 65 of its respective guide tube. and movable plate 66 disposed within the guide tube 64. Flexible cables 67 .areconnected at one" of the ends thereof to plates 66 and at the other of the ends thereof to tie rod passing over guide pulleys 68 in the process.

' Mechanism 60- also] includes a pair of quick opening springs 69 disposed within a housing form of two sections 70, .71, fora purpose to be hereinafter explained. Section 70 is mounted for limited movement with respect to section 71.=thr ough pins 72 and elongated slots (not shown). At the last limited amount of the closing stroke the short-rounded end ofarm 47 near pivot 50 picks up housing portion 70* to compress 6 9 that housing por-f the travel of cam 40 when the high point 72' thereof engages cam roller 42, limit adjusting screw 73 strikes upturned arm 74 of clutch release plate 75 causing rotation of plate 75 about its pivot opening '76 which is mounted upon a rounded hub portion 77 of cam 49.

I As plate '75 rotates counterclockwise the cam action of plate edge 73, in engagement with roller 79, causes the supportcrank arm 36 for roller 79 to pivot clockwise with respect to FIGURE 5 about pin 81. Crank arm 8%} is keyed to pin 81 as are arms 32 whose free ends engage shoulder 83 of clutch member 37 to move clutch member 37 against the force of biasing spring 39 to allow closing motor 28 to coastto a stop. A suitable limit switch 125 is provided to deenergize motor 28 when cam 46 is a predetermined angular position as when' roller 42 is at. a position clockwise of high point 72;

Prior to the disengagement of clutch members 36, 37, earn roiler 42 rolls into low formation 84, adjacent to high point 72, which serves as a prop latch for circuit breaker 19 which is now in the closed position.

' During the closing operation, roller 42 initially rides on the steep slope of cam 40. During this operation of travel the load presented by opening spring 63 is light. This'load remains comparatively light until the contacts of interrupter 12 are substantially closed. At this time the heavy load presented by opening spring 69 is picked up and thereafter it is necessary to change the slope of cam 40. This change is rather abrupt to gain the necessary mechanical advantage required for final closing.

Cam roller 42 reaches high point 72' and finally passes thereover into depression 34.

As roller 42 enters depression 84 switch 125 is operated to its open position thereby deenergizing closing motor 28. However, cam 40 continues-to rotate counterclockwise under the influence of opening springs 63-69 because of the reverse slope at the entrance to depression 84. At this time the load on the clutch teeth drops to a very low value so that declutching is accomplished with extremely little stress on the clutch elements. Declutchirrg is accomplished through the engagement of adjusting screw 73 with clutch earn plate 75 (FIGURES 6 and 6A) which separates clutch parts 3637. Cam

' 4tl continues to rotate until roller 42 reaches the bottom of depression 34.

As best seen in FIGURE 1A, depression 34 is so shaped that cam 40 engages'roiler'42 at two points 102, 103. This serves to distribute the forces exerted by the loaded springs '6-3-69 thereby reducing the possibility of wear at cam .40 or roller 42.

With a trip impulse emanating from control'box 29 and received by trip shaft 52, in a manner well known to the'art, trip finger 51 is rotated in a counterclockwise direction with respect to FIGURE 1 releasing roller 53 which in turn releases links 54, 56, 58 to free the knee 49 of toggle 45, 46. The ever present pullon links 54, 56,

' 1 58 exerted by opening springs 63 and'69 wheneircuit breaker 16 is closed forces the knee of toggle 45,46 to collapse to the right with respect to FIGURE 1.

With toggle linkage 45, 46 collapsed, the heavy load on cam roller 421s released. 'A tension spring (not shown) mounted between stationary pin 86 and pin 87.0n guide sary speed. Spring 85 is useful where the camslope is.

arm 43, assisted 'by torsion spring 88, mounted on shaft '38, acts to rotate cam 40in a clockwise direction-to the reset position of FIGURE l.,"-Two return springsare directly upon cam 40 isprovided to supply the mess steep and is provided 'to assure the return of links 45,

p 46 and the resetting of. trip latch roller53 before reengaging of the clutch 36, 37. This and prevents false operation.

provides fast closing As cam 40 notates clockwise at the end of its travel to the reset position block 89 strikes upturned arm 90 of clutch cam plate 75 rotating it clockwise and releasing roller 79 which falls into recess 89a which is more deeply out than recess 85. Arms 02 release clutch part 37 allowing spring 39 to force clutch part 37 into engagement with clutch part 36.

The quick opening springs 69 have a strong but limited stroke and are utilized to overcome starting inertia, contact friction, and oil resistance to obtain a rapid parting of the contacts comprising interrupters 12. The followthrough springs 63 in tubes 64 carry the opening motion through until tie rod 60 strikes the resilient buffer 91 mounted to the inside of cover 17 and thereafter hold operating lever 47 in the open position. Cam 40, in rotating from the position of FIGURE 1 to the position of FIGURE 2, engages adjusting member 105 carried at one end of crank element 106 which is pivoted to the housing at axle 107. The other end of crank 106 at olfset arm 108 thereof carries roller 109. Tension spring 110, secured between stationary pin 44 and offset arm 108, biases crank 106 counterclockwise with respect to FIGURE 2 so that member 105 is biased toward engagement with the edge of cam 40.

Means, in this case gravity, biases elongated insulating member 111 into engagement with roller 109. Member 111 is pivoted, at the end thereof remote from the end engaging noller 109, to pin 112 extending from stationary bracket 113. It is to be noted that the portion of insulating member 111 in engagement with roller 109 is provided with a steep sloping surface 114 so that member 111, though biased counterclockwise about pivot 112 with respect to FIGURE 2, is movable by crank 106 in a clockwise direction about pivot 112, for reasons to be fully explained.

Insulating member 111, at a point intermediate the ends thereof, is straddled by a U-shaped member 115 to which blade 116 of switch 1:25 is mounted. Blade 116 carries contacts 117, 118 which are engageable with stationary contacts 119, 120, respectively. The latter two contacts are mounted in insulating relationship to insulating member 121 carried by bracket 113. Spring 122 is disposed between the arms of U-shaped member 115 and bears against insulating member 111 and switch blade 116 to bias contacts 117, 118 toward contacts 119, 120 and provide contact pressure in the closed position of Switch 125. i

Member 111, at a point intermediate the ends thereof, carries angle bracket 126 having an aperture which receives the threaded end 127 of connecting stud 128. Nuts 12 9, 130 positioned at opposite sides of bracket 126 position and secure stud 128 relative to offset arm -9. Stud 108 at the other end thereof opposite its threaded end carries pin 129 which is disposed within open ended slot 131 in one leg 132 of switch rod 130. Pins 154 and slots 155 guide rod 130 for linear axial movement.

As best seen in FIGURES 3 and 4, when crank 106 is operated to open switch .125, stud 128, switch rod 130 is moved to the right with respect to FIGURES 3 and 4. In this position slot 133 of rod 130 is positioned to receive slideable latch member 135 which comprises an angle piece carried by screw 136.

Compression spring 137 mounted to screw 136 biases member 135 upward with respect to FIGURE 4 against nut 138 carried by screw 136. Screw 136-passes through a clearance aperture at one end of arm 140 whose other bifurcated end is clamped to shaft 52 by screw 141 and nut r142. Tension spring 143 is secured at one end to fixed pin 145 and at the other end to arm 140 at the end remote from shaft 52 and acts to reset trip finger 42. Thus, ar-m 140 is biased clockwise with respect to FIG- URE 4 about shaft 52 against adjusting screw 144.

Screw 14-7 is mounted to one end of arm 148 and passes through a clearance aperture of arm 140. The other end of arm 148 is keyed to shaft 149 whose rotation is supervised by an automatic reclosing timer-integrator of known construction. A tripping operation is initiated through a counterclockwise rotation of shaft 149 with respect to FIGURE 4 which causes arms 148 and 140 to rotate counterclockwise.

This imparts counterclockwise rotation to shaft 52 thereby rotating trip finger 42 counterclockwise to trip circuit breaker 10. Initially latch checking member 135 cannot move into slot 133 of switch rod 130 because member 135 and slot 133 are misaligned. However, the motion of arm 1 40 serves to load spring 137.

When rod 130 moves to its position of FIGURE 4, closing switch is open and member 135 is aligned with slot 133. If trip finger 42 has not fully reset the angular position of shaft 52 is such that member 135 is disposed within slot 133. At this time, even if a closing operation is directed by the timer-integrator a closing operation will not be initiated since switch rod cannot move to the left with respect to FIGURE 4 to close switch 125.

Now referring more particularly to FIGURE 8, motor 28 is energized through a circuit whose terminals 168, 169 are adapted to be connected to a source of control voltage. This circuit includes normally closed switch 166 in series with closing switch 125. Switch 125 is biased toward closed position but is restrained through the action of timer integrator latch 167. It is .to be remembered that switch 125 is automatically opened at the end of each closing cycle.

' Thus, this invention provides a novel cam closed operating mechanism of simple compact construction. The construction includes a clutch so that the motor which supplies the closing power may coast to a stop. The cam includes a prop latch depression which is shaped to engage the cam roller at two points thereby halving the pressure which ordinarily is present.

This invention also provides a mechanical latch checking means which replaces a conventional switch. The latch checking means requires few inexpensive parts, is fool proof, does not increase the trip latch load, and is readily'adjustable. In addition the need for switch wiringis eliminated.

In the foregoing, the invention has been described only in connection with preferred embodiments thereof. Many variations and modifications of the principles of the invention with-in the scope of the description are obvious. Accordingly, it is to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

*1. A circuit breaker comprising a pair of cooperating contacts and a mechanism for operating said contacts into engagement; said mechanism including a collapsible linkage, a first latch means for maintaining said linkage in an extended position, a roller carried by said linkage, and a cam means operable upon said linkage at said roller to effect operation of said contacts into engagement; said cam means including a formation constructed and positioned to cooperate with said roller and form a second latch means for maintaining said linkage when extended in a position such that said contacts are engaged, said formation comprising a depression defined by walls engaging said roller at first and second peripherally separated points to distribute forces acting to separate said contacts when said linkage is extended.

2. A circuit breaker comprising a pair of cooperating contacts and a mechanism for operating said contacts into engagement; said mechanism including a collapsible linkage, a first latch means for maintaining said iinkage in an extended position, a roller carried by said linkage, and a cam means operable upon said linkage at said roller to effect operation of said contacts into engagement; said cam means including a formation constructed and positioned to cooperate with said roller and form a second latch means for maintaining said linkage when extended in a position such that said contacts are enhaving its edge in operative engagement with said roller; said formation comprising a depression in said edge within which said roller is disposed when said contacts are engaged; saidlcontactslbeing operable into engagement through rotation of said cam in a first direction about an axis normal to the plane of said cam; biasing means urging said contacts toward disengagement; said depression 'being constructed and positioned so that said roller upon entering said depression directs aforce component of said biasing means to urge said cam in said first direction until said roller reaches the'bot-torn of said depression.

3. A circuit breaker comprising a pair of cooperating contacts and amechanism for operating said contacts into engagement; said mechanism including a collapsible linkage, a first latch means for maintaining said linkage in an extended position, a roller carried by said linkage, anda cam means operable upon said linkage at said roller to effect operation of said contacts into engagement; said cam means including a formation constructed and positioned to cooperate with said roller and form a second latch means .for maintaining said linkage when extended in-a position such that said contacts are engaged; said formation comprising a depression in said cam positioned to-receive said roller when said contacts are engaged; first means including a clutch device for 4. The circuit breaker as set'forth in claim 3'also comprising an energizing circuit forsaid first means; said circuit including aswitchbiased closed and operated a open by said cammeans assaid roller enters said depression to deenergize said first means.

/ actuating said cam in a first direction for operating said linkage, a first latch means for maintaining said linkage in an extended position, and acam means operable upon said linkage to efleot operation of said contacts into engagement; said cam means including a formation constructed and positioned to provide a second latch means for maintaining said linkage when extended in a position such that said contacts are engaged, electrically energizable driving means for operating said cam means to close said contacts, an energizing circuit for said driving means including a switch operable to closed position for energizing said driving means and operable to open position when said contacts are closed, a second means operable by said first latch means to maintain said switch open after unlatching of said tirst'latch until said first latch means returns to latching position; said switch including movable contact means, a member mechanically connected to said contact means for movement in unison therewith, said second means comprising an element mechanicallyengageable with said member when said switch is open and said first latch means is not in latching position to maintain said switch open thereby preventing false closing operations of said circuit breaker.

7. A circuit breaker comprising a pair of cooperating contacts and a mechanism for operating said contacts into engagement; said mechanism including a collapsible linkage, a first latch means for maintaining said linkage in an extended position, and' a cam means operable upon said linkage to etiect operation of said contacts into engagement; said cam means including a formation constructed and positioned to provide a second latch means for maintaining said linkage when extended in a position such that said, contacts are engaged, electrically energizable driving means for operating'said cam means to close said contacts, an energizing circuit for said driving means including a switch operable to closed posi tion for energizing said driving means'and operablelto open position when said contacts are closed; said first "latch means comprising a trip finger keyed to a shaft;

5; A circuit breaker comprising a pair of cooperating 7 contacts and a mechanism for operating said contacts into engagement; said mechanism including a collapsible linkage, a first latch means for maintaining said linkage in'an extended position and a cam' means operable upon said linkage to eifect operation of said contacts into engagement; said cam means including a formation constructed and positioned to provide a' second latch means for maintaining-said [linkage when extended in a position such that said contacts are engaged, electrically a switch rod mechanic-ally connected to said switch and movablebetween a first and a second positionwherein said switch is open and closed, respectively; a latch checking member; an operative connection joining said member to said shaft for movement between a third and a fourth/position wherein said tripfinger is in latching and tripped positions, respectively; said latch checking memberiwhen in said fourth position cooperating with a formation of said switch rod when said rod is in said second position to prevent movement of said rod to said first position.

'8. The circuit breaker of claim 7 in which the operative connection comprises a yieldable portion whereby said latch checking member is biased toward saidrod.

9. The circuit breaker or" claim 8 also comprising a v trip device operable upon said operative connection to,

move said trip fingerto tripped position. 

1. A CIRCUIT BREAKER COMPRISING A PAIR OF COOPERATING CONTACTS AND A MECHANISM FOR OPERATING SAID CONTACTS INTO ENGAGEMENT; SAID MECHANISM INCLUDING A COLLAPSIBLE LINKAGE, A FIRST LATCH MEANS FOR MAINTAINING SAID LINKAGE IN AN EXTENDED POSITION, A ROLLER CARRIED BY SAID LINKAGE, AND A CAM MEANS OPERABLE UPON SAID LINKAGE AT SAID ROLLER TO EFFECT OPERATION OF SAID CONTACTS INTO ENGAGEMENT; SAID CAM MEANS INCLUDING A FORMATION CONSTRUCTED AND POSITIONED TO COOPERATE WITH SAID ROLLER AND FORM A SECOND LATCH MEANS FOR MAINTAINING SAID LINKAGE WHEN EXTENDED IN A POSITION SUCH THAT SAID CONTACTS ARE ENGAGED, SAID FORMATION COMPRISING A DEPRESSION DEFINED BY WALLS ENGAGING SAID ROLLER AT FIRST AND SECOND PERIPH- 